A light source that is created by a light emitting diode (LED). For decades, LEDs have been used as indicator lights on myriad products; however, starting in the 2000s, they began to replace incandescent, halogen and fluorescent bulbs. LEDs draw considerably less power and are up to 80% more efficient. Although claims are made for some bulbs lasting 30 years, one should expect at least a 10-year life span under normal usage.

In Their Infancy
As of 2014, LED bulbs are still considerably more expensive than incandescent bulbs; however, prices are constantly decreasing. Companies are experimenting with numerous designs, as there is more than one way to make LED lights. For example, when red, green and blue LEDs are combined, they produce white light. Another method uses a blue LED and yellow or red phosphors.

New Lights - A Different Power Source
As incandescent bulbs are replaced with LED bulbs using the same Edison screw mount, the LED bulb must include AC to DC conversion. However, if the bulb's power source is DC such as from powered Ethernet, they are more efficient (see POE and Edison base). See incandescent bulb, halogen bulb, fluorescent bulb and LED.

Incandescent Vs. LED

The LED bulb on the right draws 3.5 watts but delivers the same brightness as the 45-watt bulb on the left. This LED bulb casts a very white light; however, LED bulbs run the gamut from warm yellow to white-blue (see color temperature).

21st Century Light Bulbs

These 75-watt bulbs cast the same warm glow people like about incandescent bulbs. (Images courtesy of Switch Bulb Company, Inc., and Philips Electronics N.V.)

LED Night Light - 23 Times Less Power

Instead of the 7 watt incandescent bulb in the typical night light, this LED uses 0.3 watts. The blue arrow points to the single LED; the red arrow shows the light sensor.

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